Online cluster-finding algorithms for the PANDA electromagnetic calorimeter

Om zeldzame processen zoals de vorming van exotische deeltjes te kunnen bestuderen, is het PANDA experiment opgezet. Om de grote hoeveelheden data te kunnen verwerken, verwerken de subsystemen de data voor. Een voorbeeld is het algoritme om online naar clusters te zoeken in de data van de caloriemeter, in dit proefschrift ontwikkeld. Vanwege de hoge interactiesnelheden is de tijd belangrijk. Optima zijn bepaald om de data in (tijds)groepen (257, 97 en 15 ns) en de treffers aan clusters (282, 122, en 40 ns) in te delen, voor interactiesnelheden van 200 kHz en minder, 2 MHz, en 20 MHz, respectievelijk, en treffers moesten minimaal 3 MeV hebben. Met de gevonden optima zijn de efficienties voor de twee- en zeven-fotonenkanalen die onderzocht zijn respectievelijk 70-80% en 9-20%, afhankelijk van de interactiesnelheid. Hiernaast is onderzocht of dit algoritme op het uitleessysteem kan draaien, waarbij gebruik gemaakt wordt van rekenkracht in de dataverzamelaars en de knooppunten in het dataverzamelingsnetwerk. Dit blijkt te kunnen, en bovendien is de tijd die nodig is om de data te verwerken per saldo lager met deze aanpak. Een belangrijke voetnoot bij de efficienties is dat er enkele problemen waren met de toekenning van tijdstempels aan de treffers, waardoor deze resultaten kunnen afwijken van de werkelijkheid. Daarnaast moet er nog een stap in de reconstructie worden toegevoegd, waar de gebeurtenisselectie plaatsvindt om de uiteindelijke efficienties te kunnen bepalen. Het wordt aangeraden om verder te gaan met de ontwikkeling van het clusterzoekalgoritme, gezien het goede prestaties tegen lage kosten levert.To study rare processes, such as the formation of exotic particles, the PANDA experiment has been set up. To process the large dataflow, the subsystems preprocess the data. One example is the algorithm to search online for clusters in the data of the calorimeter, developed in this thesis. Due to the high interaction rates, the time is important. Optima have been determined to assign the data to (time)bunches (257, 97, and 15 ns) and hits to clusters (282, 122, and 40 ns), for interaction rates of 200 kHz and less, 2 MHz, and 20 MHz, respectively, and each hit must have a minimal energy of 3 MeV. Using these optima, the efficiencies for the investigated two- and seven-photon channels are 70-80% and 9-20%, respectively, depending on the interaction rate. In addition, it was investigated if the algorithm can run on the readout system, making use of the processing power in the data concentrators and the nodes in the data collection network. This was found to be possible, and, furthermore, the processing time using this approach is much lower. An important note to the efficiencies is that there were problems in creating the time stamps for the hits, which may cause the obtained results to deviate from reality. In addition, another step needs to be added to the reconstruction, where the event selection takes place, to determine the final efficiencies. It is recommended to proceed with the development of the cluster finding algorithm, as it delivers good performance at low costs

Measurement of e+ e− → Dbar D cross sections at the ψ(3770) resonance*

Chinese Physics C Paper • The following article is OPEN ACCESS Measurement of e+ e− → Dbar D cross sections at the ψ(3770) resonance* M. Ablikim (麦迪娜)1, M. N. Achasov9,71, S. Ahmed14, M. Albrecht4, M. Alekseev60,62, A. Amoroso60,62, F. F. An (安芬芬)1, Q. An (安琪)44,57, Y. Bai (白羽)43, O. Bakina28, R. Baldini Ferroli22, Y. Ban (班勇)36, K. Begzsuren26, D. W. Bennett21, J. V. Bennett5, N. Berger27, M. Bertani22, D. Bettoni24, J. M. Bian (边渐鸣)54, F. Bianchi60,62, E. Boger28,69, I. Boyko28, R. A. Briere5, H. Cai (蔡浩)64, X. Cai (蔡啸)1,44, O. Cakir47, A. Calcaterra22, G. F. Cao (曹国富)1,51, S. A. Cetin48, J. Chai62, J. F. Chang (常劲帆)1,44, W. L. Chang1,51, G. Chelkov28,69,70, G. Chen (陈刚)1, H. S. Chen (陈和生)1,51, J. C. Chen (陈江川)1, M. L. Chen (陈玛丽)1,44, P. L. Chen (陈平亮)58, S. J. Chen (陈申见)34, X. R. Chen (陈旭荣)31, Y. B. Chen (陈元柏)1,44, X. K. Chu (褚新坤)36, G. Cibinetto24, F. Cossio62, H. L. Dai (代洪亮)1,44, J. P. Dai (代建平)39,75, A. Dbeyssi14, D. Dedovich28, Z. Y. Deng (邓子艳)1, A. Denig27, I. Denysenko28, M. Destefanis60,62, F. De Mori60,62, Y. Ding (丁勇)32, C. Dong (董超)35, J. Dong (董静)1,44, L. Y. Dong (董燎原)1,51, M. Y. Dong (董明义)1, Z. L. Dou (豆正磊)34, S. X. Du (杜书先)67, P. F. Duan (段鹏飞)1, J. Fang (方建)1,44, S. S. Fang (房双世)1,51, Y. Fang (方易)1, R. Farinelli24,25, L. Fava61,62, S. Fegan27, F. Feldbauer4, G. Felici22, C. Q. Feng (封常青)44,57, E. Fioravanti24, M. Fritsch4, C. D. Fu (傅成栋)1, Q. Gao (高清)1, X. L. Gao (高鑫磊)44,57, Y. Gao (高原宁)46, Y. G. Gao (高勇贵)6, Z. Gao (高榛)44,57, B. Garillon27, I. Garzia24, A. Gilman54, K. Goetzen10, L. Gong (龚丽)35, W. X. Gong (龚文煊)1,44, W. Gradl27, M. Greco60,62, L. M. Gu (谷立民)34, M. H. Gu (顾旻皓)1,44, Y. T. Gu (顾运厅)12, A. Q. Guo (郭爱强)1, L. B. Guo (郭立波)33, R. P. Guo (郭如盼)1,51, Y. P. Guo (郭玉萍)27, A. Guskov28, Z. Haddadi30, S. Han (韩爽)64, X. Q. Hao (郝喜庆)15, F. A. Harris52, K. L. He (何康林)1,51, X. Q. He (何希勤)56, F. H. Heinsius4, T. Held4, Y. K. Heng (衡月昆)1, T. Holtmann4, Z. L. Hou (侯治龙)1, H. M. Hu (胡海明)1,51, J. F. Hu (胡继峰)39,75, T. Hu (胡涛)1, Y. Hu (胡誉)1, G. S. Huang (黄光顺)44,57, J. S. Huang (黄金书)15, X. T. Huang (黄性涛)38, X. Z. Huang (黄晓忠)34, Z. L. Huang (黄智玲)32, T. Hussain59, W. Ikegami Andersson63, M Irshad44,57, Q. Ji (纪全)1, Q. P. Ji (姬清平)15, X. B. Ji (季晓斌)1,51, X. L. Ji (季筱璐)2, X. S. Jiang (江晓山)1, X. Y. Jiang (蒋兴雨)35, J. B. Jiao (焦健斌)38, Z. Jiao (焦铮)17, D. P. Jin (金大鹏)1, S. Jin (金山)1,51, Y. Jin (金毅)53, T. Johansson63, A. Julin54, N. Kalantar-Nayestanaki30, X. S. Kang (康晓珅)35, M. Kavatsyuk30, B. C. Ke (柯百谦)1, T. Khan44,57, A. Khoukaz55, P. Kiese27, R. Kliemt10, L. Koch29, O. B. Kolcu48,73, B. Kopf4, M. Kornicer52, M. Kuemmel4, M. Kuessner4, A. Kupsc63, M. Kurth1, W. Kuhn29, J. S. Lange29, M. Lara21, P. Larin14, L. Lavezzi62,1, S. Leiber4, H. Leithoff27, C. Li (李翠)63, Cheng Li (李澄)44,57, D. M. Li (李德民)67, F. Li (李飞)1,44, F. Y. Li (李峰云)36, G. Li (李刚)1, H. B. Li (李海波)1,51, H. J. Li (李惠静)1,51, J. C. Li (李家才)1, J. W. Li (李井文)42, K. J. Li (李凯杰)45, Kang Li (李康)13, Ke Li (李科)1, Lei Li (李蕾)3, P. L. Li (李佩莲)44,57, P. R. Li (李培荣)7,51, Q. Y. Li (李启云)38, T. Li (李腾)38, W. D. Li (李卫东)1,51, W. G. Li (李卫国)1, X. L. Li (李晓玲)38, X. N. Li (李小男)1,44, X. Q. Li (李学潜)35, Z. B. Li (李志兵)45, H. Liang (梁昊)44,57, Y. F. Liang (梁勇飞)41, Y. T. Liang (梁羽铁)29, G. R. Liao (廖广睿)11, L. Z. Liao (廖龙洲)1,51, J. Libby20, C. X. Lin (林创新)45, D. X. Lin (林德旭)14, B. Liu (刘冰)39,75, B. J. Liu (刘北江)1, C. X. Liu (刘春秀)1, D. Liu (刘栋)44,57, D. Y. Liu (刘殿宇)39,75, F. H. Liu (刘福虎)40, Fang Liu (刘芳)1, Feng Liu (刘峰)6, H. B. Liu (刘宏邦)12, H. L Liu (刘恒君)43, H. M. Liu (刘怀民)1,51, Huanhuan Liu (刘欢)1, Huihui Liu (刘汇慧)16, J. B. Liu (刘建北)44,57, J. Y. Liu (刘晶译)1,51, K. Liu (刘凯)46, K. Y. Liu (刘魁勇)32, Ke Liu (刘珂)6, L. D. Liu (刘兰雕)36, Q. Liu (刘倩)51, S. B. Liu (刘树彬)44,57, X. Liu (刘翔)31, Y. B. Liu (刘玉斌)35, Z. A. Liu (刘振安)1, Zhiqing Liu (刘智青)27, Y. F. Long (龙云飞)36, X. C. Lou (娄辛犴)1, H. J. Lu (吕海江)17, J. G. Lu (吕军光)1,44, Y. Lu (卢宇)1, Y. P. Lu (卢云鹏)1,44, C. L. Luo (罗成林)33, M. X. Luo (罗民兴)66, X. L. Luo (罗小兰)1,44, S. Lusso62, X. R. Lyu (吕晓睿)51, F. C. Ma (马凤才)32, H. L. Ma (马海龙)1, L. L. Ma (马连良)38, M. M. Ma (马明明)1,51, Q. M. Ma (马秋梅)1, X. N. Ma (马旭宁)35, X. Y. Ma (马骁妍)1,44, Y. M. Ma (马玉明)38, F. E. Maas14, M. Maggiora60,62, Q. A. Malik59, A. Mangoni23, Y. J. Mao (冒亚军)36, Z. P. Mao (毛泽普)1, S. Marcello60,62, Z. X. Meng (孟召霞)53, J. G. Messchendorp30, G. Mezzadri24, J. Min (闵建)1,44, T. J. Min (闵天觉)1, R. E. Mitchell21, X. H. Mo (莫晓虎)1, Y. J. Mo (莫玉俊)6, C. Morales Morales14, G. Morello22, N. Yu. Muchnoi9,71, H. Muramatsu (村松創)54, A. Mustafa4, S. Nakhoul10,74, Y. Nefedov28, F. Nerling10, I. B. Nikolaev9,71, Z. Ning (宁哲)1,44, S. Nisar8, S. L. Niu (牛顺利)1,44, X. Y. Niu (牛讯伊)1,51, S. L. Olsen (馬鵬)37,77, Q. Ouyang (欧阳群)1, S. Pacetti23, Y. Pan (潘越)44,57, M. Papenbrock63, P. Patteri22, M. Pelizaeus4, J. Pellegrino60,62, H. P. Peng (彭海平)44,57, Z. Y. Peng (彭志远)12, K. Peters10,74, J. Pettersson63, J. L. Ping (平加伦)33, R. G. Ping (平荣刚)1,51, A. Pitka4, R. Poling54, V. Prasad44,57, H. R. Qi (漆红荣)2, M. Qi (祁鸣)34, T. Y. Qi (齐天钰)2, S. Qian (钱森)1,44, C. F. Qiao (乔从丰)51, N. Qin (覃拈)64, X. S. Qin4, Z. H. Qin (秦中华)1,44, J. F. Qiu (邱进发)1, K. H. Rashid59,76, C. F. Redmer27, M. Richter4, M. Ripka27, M. Rolo62, G. Rong (荣刚)1,51, Ch. Rosner14, X. D. Ruan (阮向东)12, A. Sarantsev28,72, M. Savrie25, C. Schnier4, K. Schoenning63, W. Shan (单葳)18, X. Y. Shan (单心钰)44,57, M. Shao (邵明)44,57, C. P. Shen (沈成平)2, P. X. Shen (沈培迅)35, X. Y. Shen (沈肖雁)1,51, H. Y. Sheng (盛华义)1, X. Shi (史欣)1,44, J. J. Song (宋娇娇)38, W. M. Song38, X. Y. Song (宋欣颖)1, S. Sosio60,62, C. Sowa4, S. Spataro60,62, G. X. Sun (孙功星)1, J. F. Sun (孙俊峰)15, L. Sun (孙亮)64, S. S. Sun (孙胜森)1,51, X. H. Sun (孙新华)1, Y. J. Sun (孙勇杰)44,57, Y. K Sun (孙艳坤)44,57, Y. Z. Sun (孙永昭)1, Z. J. Sun (孙志嘉)1,44, Z. T. Sun (孙振田)21, Y. T Tan (谭雅星)44,57, C. J. Tang (唐昌建)41, G. Y. Tang (唐光毅)1, X. Tang (唐晓)1, I. Tapan49, M. Tiemens30, D. Toth54, B. Tsednee26, I. Uman50, G. S. Varner52, B. Wang (王斌)1, B. L. Wang (王滨龙)51, C. W. Wang (王成伟)34, D. Wang (王东)36, D. Y. Wang (王大勇)36, Dan Wang (王丹)51, K. Wang (王科)1,44, L. L. Wang (王亮亮)1, L. S. Wang (王灵淑)1, M. Wang (王萌)38, Meng Wang (王蒙)1,51, P. Wang (王平)1, P. L. Wang (王佩良)1, W. P. Wang (王维平)44,57, X. F. Wang (王雄飞)1, Y. Wang (王越)44,57, Y. F. Wang (王贻芳)27, Y. Q. Wang (王亚乾)27, Z. Wang (王铮)1,44, Z. G. Wang (王志刚)1,44, Z. Y. Wang (王至勇)1, Zongyuan Wang (王宗源)1,51, T. Weber4, D. H. Wei (魏代会)11, P. Weidenkaff27, S. P. Wen (文硕频)1, U. Wiedner4, M. Wolke63, L. H. Wu (伍灵慧)1, L. J. Wu (吴连近)1,51, Z. Wu (吴智)1,44, L. Xia (夏磊)44,57, X. Xia38, Y. Xia (夏宇)19, D. Xiao (肖栋)1, Y. J. Xiao (肖言佳)1,51, Z. J. Xiao (肖振军)33, Y. G. Xie (谢宇广)1,44, Y. H. Xie (谢跃红)6, X. A. Xiong (熊习安)1,51, Q. L. Xiu (修青磊)1,44, G. F. Xu (许国发)1, J. J. Xu (徐静静)1,51, L. Xu (徐雷)1, Q. J. Xu (徐庆君)13, Q. N. Xu (徐庆年)51, X. P. Xu (徐新平)42, F. Yan (严芳)58, L. Yan (严亮)60,62, W. B. Yan (鄢文标)44,57, W. C. Yan (闰文成)2, Y. H. Yan (颜永红)19, H. J. Yang (杨海军)39,75, H. X. Yang (杨洪勋)1, L. Yang (杨柳)64, S. L. Yang (杨双莉)1,51, Y. H. Yang (杨友华)34, Y. X. Yang (杨永栩)11, Yifan Yang (杨翊凡)1,51, M. Ye (叶梅)1,44, M. H. Ye (叶铭汉)7, J. H. Yin (殷俊昊)1, Z. Y. You (尤郑昀)45, B. X. Yu (俞伯祥)1, C. X. Yu (喻纯旭)35, J. S. Yu (俞洁晟)31, C. Z. Yuan (苑长征)1,51, Y. Yuan (袁野)1, A. Yuncu48,68, A. A. Zafar59, A. Zallo22, Y. Zeng (曾云)19, Z. Zeng (曾哲)44,57, B. X. Zhang (张丙新)1, B. Y. Zhang (张炳云)1,44, C. C. Zhang (张长春)1, D. H. Zhang (张达华)1, H. H. Zhang (张宏浩)45, H. Y. Zhang (章红宇)1,44, J. Zhang (张晋)1,51, J. L. Zhang (张杰磊)65, J. Q. Zhang4, J. W. Zhang (张家文)1, J. Y. Zhang (张建勇)1, J. Z. Zhang (张景芝)1,51, K. Zhang (张坤)1,51, L. Zhang (张磊)46, S. F. Zhang (张思凡)34, T. J. Zhang (张天骄)39,75, X. Y. Zhang (张学尧)38, Y. Zhang (张言)44,57, Y. H. Zhang (张银鸿)1,44, Y. T. Zhang (张亚腾)44,57, Yang Zhang (张洋)1, Yao Zhang (张瑶)1, Yu Zhang (张宇)51, Z. H. Zhang (张正好)6, Z. P. Zhang (张子平)57, Z. Y. Zhang (张振宇)64, G. Zhao (赵光)1, J. W. Zhao (赵京伟)1,44, J. Y. Zhao (赵静宜)1,51, J. Z. Zhao (赵京周)1,44, Lei Zhao (赵雷)44,57, Ling Zhao (赵玲)1, M. G. Zhao (赵明刚)35, Q. Zhao (赵强)1, S. J. Zhao (赵书俊)67, T. C. Zhao (赵天池)1, Y. B. Zhao (赵豫斌)1,44, Z. G. Zhao (赵政国)44,57, A. Zhemchugov28,69, B. Zheng (郑波)58, J. P. Zheng (郑建平)1,44, W. J. Zheng (郑文静)38, Y. H. Zheng (郑阳恒)51, B. Zhong (钟彬)33, L. Zhou (周莉)1,44, Q. Zhou (周巧)1,51, X. Zhou (周详)64, X. K. Zhou (周晓康)44,57, X. R. Zhou (周小蓉)44,57, X. Y. Zhou (周兴玉)1, A. N. Zhu (朱傲男)1,51, J. Zhu (朱江)35, J. Zhu (朱江)45, K. Zhu (朱凯)1, K. J. Zhu (朱科军)1, S. Zhu (朱帅)1, S. H. Zhu (朱世海)56, X. L. Zhu (朱相雷)46, Y. C. Zhu (朱莹春)44,57, Y. S. Zhu (朱永生)1,51, Z. A. Zhu (朱自安)1,51, J. Zhuang (庄建)1,44, B. S. Zou (邹冰松)1, J. H. Zou (邹佳恒)1 and BESIII CollaborationHide full author list © 2018 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd Chinese Physics C, Volume 42, Number 8 Download Article PDF Figures References Download PDF 523 Total downloads 1 1 citation on Dimensions. Article has an altmetric score of 3 Turn on MathJax Share this article Share this content via email Share on Facebook Share on Twitter Share on Google+ Share on CiteULike Share on Mendeley Hide article information Author affiliations 1 Institute of High Energy Physics, Beijing 100049, China 2 Beihang University, Beijing 100191, China 3 Beijing Institute of Petrochemical Technology, Beijing 102617, China 4 Bochum Ruhr-University, D-44780 Bochum, Germany 5 Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA 6 Central China Normal University, Wuhan 430079, China 7 China Center of Advanced Science and Technology, Beijing 100190, China 8 COMSATS Institute of Information Technology, Lahore, Defence Road, Off Raiwind Road, 54000 Lahore, Pakistan 9 G.I. Budker Institute of Nuclear Physics SB RAS (BINP), Novosibirsk 630090, Russia 10 GSI Helmholtzcentre for Heavy Ion Research GmbH, D-64291 Darmstadt, Germany 11 Guangxi Normal University, Guilin 541004, China 12 Guangxi University, Nanning 530004, China 13 Hangzhou Normal University, Hangzhou 310036, China 14 Helmholtz Institute Mainz, Johann-Joachim-Becher-Weg 45, D-55099 Mainz, Germany 15 Henan Normal University, Xinxiang 453007, China 16 Henan University of Science and Technology, Luoyang 471003, China 17 Huangshan College, Huangshan 245000, China 18 Hunan Normal University, Changsha 410081, China 19 Hunan University, Changsha 410082, China 20 Indian Institute of Technology Madras, Chennai 600036, India 21 Indiana University, Bloomington, Indiana 47405, USA 22 INFN Laboratori Nazionali di Frascati, I-00044, Frascati, Italy 23 INFN and University of Perugia, I-06100, Perugia, Italy 24 INFN Sezione di Ferrara, I-44122, Ferrara, Italy 25 University of Ferrara, I-44122, Ferrara, Italy 26 Institute of Physics and Technology, Peace Ave. 54B, Ulaanbaatar 13330, Mongolia 27 Johannes Gutenberg University of Mainz, Johann-Joachim-Becher-Weg 45, D-55099 Mainz, Germany 28 Joint Institute for Nuclear Research, 141980 Dubna, Moscow region, Russia 29 Justus-Liebig-Universitaet Giessen, II. Physikalisches Institut, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany 30 KVI-CART, University of Groningen, NL-9747 AA Groningen, The Netherlands 31 Lanzhou University, Lanzhou 730000, China 32 Liaoning University, Shenyang 110036, China 33 Nanjing Normal University, Nanjing 210023, China 34 Nanjing University, Nanjing 210093, China 35 Nankai University, Tianjin 300071, China 36 Peking University, Beijing 100871, China 37 Seoul National University, Seoul, 151-747, Korea 38 Shandong University, Jinan 250100, China 39 Shanghai Jiao Tong University, Shanghai 200240, China 40 Shanxi University, Taiyuan 030006, China 41 Sichuan University, Chengdu 610064, China 42 Soochow University, Suzhou 215006, China 43 Southeast University, Nanjing 211100, China 44 State Key Laboratory of Particle Detection and Electronics, Beijing 100049, Hefei 230026, China 45 Sun Yat-Sen University, Guangzhou 510275, China 46 Tsinghua University, Beijing 100084, China 47 Ankara University, 06100 Tandogan, Ankara, Turkey 48 Istanbul Bilgi University, 34060 Eyup, Istanbul, Turkey 49 Uludag University, 16059 Bursa, Turkey 50 Near East University, Nicosia, North Cyprus, Mersin 10, Turkey 51 University of Chinese Academy of Sciences, Beijing 100049, China 52 University of Hawaii, Honolulu, Hawaii 96822, USA 53 University of Jinan, Jinan 250022, China 54 University of Minnesota, Minneapolis, Minnesota 55455, USA 55 University of Muenster, Wilhelm-Klemm-Str. 9, 48149 Muenster, Germany 56 University of Science and Technology Liaoning, Anshan 114051, China 57 University of Science and Technology of China, Hefei 230026, China 58 University of South China, Hengyang 421001, China 59 University of the Punjab, Lahore-54590, Pakistan 60 University of Turin, I-10125, Turin, Italy 61 University of Eastern Piedmont, I-15121, Alessandria, Italy 62 INFN, I-10125, Turin, Italy 63 Uppsala University, Box 516, SE-75120 Uppsala, Sweden 64 Wuhan University, Wuhan 430072, China 65 Xinyang Normal University, Xinyang 464000, China 66 Zhejiang University, Hangzhou 310027, China 67 Zhengzhou University, Zhengzhou 450001, China 68 Also at Bogazici University, 34342 Istanbul, Turkey 69 Also at the Moscow Institute of Physics and Technology, Moscow 141700, Russia 70 Also at the Functional Electronics Laboratory, Tomsk State University, Tomsk, 634050, Russia 71 Also at the Novosibirsk State University, Novosibirsk, 630090, Russia 72 Also at the NRC "Kurchatov Institute", PNPI, 188300, Gatchina, Russia 73 Also at Istanbul Arel University, 34295 Istanbul, Turkey 74 Also at Goethe University Frankfurt, 60323 Frankfurt am Main, Germany 75 Also at Key Laboratory for Particle Physics, Astrophysics and Cosmology, Ministry of Education; Shanghai Key Laboratory for Particle Physics and Cosmology; Institute of Nuclear and Particle Physics, Shanghai 200240, China 76 Also at Government College Women University, Sialkot - 51310. Punjab, Pakistan 77 Currently at: Center for Underground Physics, Institute for Basic Science, Daejeon 34126, Korea Dates Received 17 March 2018 Citation M. Ablikim et al 2018 Chinese Phys. C 42 083001 Create citation alert DOI https://doi.org/10.1088/1674-1137/42/8/083001 E-print http://arxiv.org/abs/1803.06293 Journal RSS feed Sign up for new issue notifications Abstract We report new measurements of the cross sections for the production of Dbar D final states at the ψ(3770) resonance. Our data sample consists of an integrated luminosity of 2.93 fb−1 of e+e− annihilation data produced by the BEPCII collider and collected and analyzed with the BESIII detector. We exclusively reconstruct three D0 and six D+ hadronic decay modes and use the ratio of the yield of fully reconstructed Dbar D events ("double tags") to the yield of all reconstructed D or bar D mesons ("single tags") to determine the number of D0bar D0 and D+D− events, benefiting from the cancellation of many systematic uncertainties. Combining these yields with an independent determination of the integrated luminosity of the data sample, we find the cross sections to be σ(e+e− → D0bar D0) nb and σ(e+e− → D+D−) = (2.830 ± 0.011 ± 0.026) nb, where the uncertainties are statistical and systematic, respectively. Chinese Physics C Paper • The following article is OPEN ACCESS Measurement of e+ e− → Dbar D cross sections at the ψ(3770) resonance* M. Ablikim (麦迪娜)1, M. N. Achasov9,71, S. Ahmed14, M. Albrecht4, M. Alekseev60,62, A. Amoroso60,62, F. F. An (安芬芬)1, Q. An (安琪)44,57, Y. Bai (白羽)43, O. Bakina28, R. Baldini Ferroli22, Y. Ban (班勇)36, K. Begzsuren26, D. W. Bennett21, J. V. Bennett5, N. Berger27, M. Bertani22, D. Bettoni24, J. M. Bian (边渐鸣)54, F. Bianchi60,62, E. Boger28,69, I. Boyko28, R. A. Briere5, H. Cai (蔡浩)64, X. Cai (蔡啸)1,44, O. Cakir47, A. Calcaterra22, G. F. Cao (曹国富)1,51, S. A. Cetin48, J. Chai62, J. F. Chang (常劲帆)1,44, W. L. Chang1,51, G. Chelkov28,69,70, G. Chen (陈刚)1, H. S. Chen (陈和生)1,51, J. C. Chen (陈江川)1, M. L. Chen (陈玛丽)1,44, P. L. Chen (陈平亮)58, S. J. Chen (陈申见)34, X. R. Chen (陈旭荣)31, Y. B. Chen (陈元柏)1,44, X. K. Chu (褚新坤)36, G. Cibinetto24, F. Cossio62, H. L. Dai (代洪亮)1,44, J. P. Dai (代建平)39,75, A. Dbeyssi14, D. Dedovich28, Z. Y. Deng (邓子艳)1, A. Denig27, I. Denysenko28, M. Destefanis60,62, F. De Mori60,62, Y. Ding (丁勇)32, C. Dong (董超)35, J. Dong (董静)1,44, L. Y. Dong (董燎原)1,51, M. Y. Dong (董明义)1, Z. L. Dou (豆正磊)34, S. X. Du (杜书先)67, P. F. Duan (段鹏飞)1, J. Fang (方建)1,44, S. S. Fang (房双世)1,51, Y. Fang (方易)1, R. Farinelli24,25, L. Fava61,62, S. Fegan27, F. Feldbauer4, G. Felici22, C. Q. Feng (封常青)44,57, E. Fioravanti24, M. Fritsch4, C. D. Fu (傅成栋)1, Q. Gao (高清)1, X. L. Gao (高鑫磊)44,57, Y. Gao (高原宁)46, Y. G. Gao (高勇贵)6, Z. Gao (高榛)44,57, B. Garillon27, I. Garzia24, A. Gilman54, K. Goetzen10, L. Gong (龚丽)35, W. X. Gong (龚文煊)1,44, W. Gradl27, M. Greco60,62, L. M. Gu (谷立民)34, M. H. Gu (顾旻皓)1,44, Y. T. Gu (顾运厅)12, A. Q. Guo (郭爱强)1, L. B. Guo (郭立波)33, R. P. Guo (郭如盼)1,51, Y. P. Guo (郭玉萍)27, A. Guskov28, Z. Haddadi30, S. Han (韩爽)64, X. Q. Hao (郝喜庆)15, F. A. Harris52, K. L. He (何康林)1,51, X. Q. He (何希勤)56, F. H. Heinsius4, T. Held4, Y. K. Heng (衡月昆)1, T. Holtmann4, Z. L. Hou (侯治龙)1, H. M. Hu (胡海明)1,51, J. F. Hu (胡继峰)39,75, T. Hu (胡涛)1, Y. Hu (胡誉)1, G. S. Huang (黄光顺)44,57, J. S. Huang (黄金书)15, X. T. Huang (黄性涛)38, X. Z. Huang (黄晓忠)34, Z. L. Huang (黄智玲)32, T. Hussain59, W. Ikegami Andersson63, M Irshad44,57, Q. Ji (纪全)1, Q. P. Ji (姬清平)15, X. B. Ji (季晓斌)1,51, X. L. Ji (季筱璐)2, X. S. Jiang (江晓山)1, X. Y. Jiang (蒋兴雨)35, J. B. Jiao (焦健斌)38, Z. Jiao (焦铮)17, D. P. Jin (金大鹏)1, S. Jin (金山)1,51, Y. Jin (金毅)53, T. Johansson63, A. Julin54, N. Kalantar-Nayestanaki30, X. S. Kang (康晓珅)35, M. Kavatsyuk30, B. C. Ke (柯百谦)1, T. Khan44,57, A. Khoukaz55, P. Kiese27, R. Kliemt10, L. Koch29, O. B. Kolcu48,73, B. Kopf4, M. Kornicer52, M. Kuemmel4, M. Kuessner4, A. Kupsc63, M. Kurth1, W. Kuhn29, J. S. Lange29, M. Lara21, P. Larin14, L. Lavezzi62,1, S. Leiber4, H. Leithoff27, C. Li (李翠)63, Cheng Li (李澄)44,57, D. M. Li (李德民)67, F. Li (李飞)1,44, F. Y. Li (李峰云)36, G. Li (李刚)1, H. B. Li (李海波)1,51, H. J. Li (李惠静)1,51, J. C. Li (李家才)1, J. W. Li (李井文)42, K. J. Li (李凯杰)45, Kang Li (李康)13, Ke Li (李科)1, Lei Li (李蕾)3, P. L. Li (李佩莲)44,57, P. R. Li (李培荣)7,51, Q. Y. Li (李启云)38, T. Li (李腾)38, W. D. Li (李卫东)1,51, W. G. Li (李卫国)1, X. L. Li (李晓玲)38, X. N. Li (李小男)1,44, X. Q. Li (李学潜)35, Z. B. Li (李志兵)45, H. Liang (梁昊)44,57, Y. F. Liang (梁勇飞)41, Y. T. Liang (梁羽铁)29, G. R. Liao (廖广睿)11, L. Z. Liao (廖龙洲)1,51, J. Libby20, C. X. Lin (林创新)45, D. X. Lin (林德旭)14, B. Liu (刘冰)39,75, B. J. Liu (刘北江)1, C. X. Liu (刘春秀)1, D. Liu (刘栋)44,57, D. Y. Liu (刘殿宇)39,75, F. H. Liu (刘福虎)40, Fang Liu (刘芳)1, Feng Liu (刘峰)6, H. B. Liu (刘宏邦)12, H. L Liu (刘恒君)43, H. M. Liu (刘怀民)1,51, Huanhuan Liu (刘欢)1, Huihui Liu (刘汇慧)16, J. B. Liu (刘建北)44,57, J. Y. Liu (刘晶译)1,51, K. Liu (刘凯)46, K. Y. Liu (刘魁勇)32, Ke Liu (刘珂)6, L. D. Liu (刘兰雕)36, Q. Liu (刘倩)51, S. B. Liu (刘树彬)44,57, X. Liu (刘翔)31, Y. B. Liu (刘玉斌)35, Z. A. Liu (刘振安)1, Zhiqing Liu (刘智青)27, Y. F. Long (龙云飞)36, X. C. Lou (娄辛犴)1, H. J. Lu (吕海江)17, J. G. Lu (吕军光)1,44, Y. Lu (卢宇)1, Y. P. Lu (卢云鹏)1,44, C. L. Luo (罗成林)33, M. X. Luo (罗民兴)66, X. L. Luo (罗小兰)1,44, S. Lusso62, X. R. Lyu (吕晓睿)51, F. C. Ma (马凤才)32, H. L. Ma (马海龙)1, L. L. Ma (马连良)38, M. M. Ma (马明明)1,51, Q. M. Ma (马秋梅)1, X. N. Ma (马旭宁)35, X. Y. Ma (马骁妍)1,44, Y. M. Ma (马玉明)38, F. E. Maas14, M. Maggiora60,62, Q. A. Malik59, A. Mangoni23, Y. J. Mao (冒亚军)36, Z. P. Mao (毛泽普)1, S. Marcello60,62, Z. X. Meng (孟召霞)53, J. G. Messchendorp30, G. Mezzadri24, J. Min (闵建)1,44, T. J. Min (闵天觉)1, R. E. Mitchell21, X. H. Mo (莫晓虎)1, Y. J. Mo (莫玉俊)6, C. Morales Morales14, G. Morello22, N. Yu. Muchnoi9,71, H. Muramatsu (村松創)54, A. Mustafa4, S. Nakhoul10,74, Y. Nefedov28, F. Nerling10, I. B. Nikolaev9,71, Z. Ning (宁哲)1,44, S. Nisar8, S. L. Niu (牛顺利)1,44, X. Y. Niu (牛讯伊)1,51, S. L. Olsen (馬鵬)37,77, Q. Ouyang (欧阳群)1, S. Pacetti23, Y. Pan (潘越)44,57, M. Papenbrock63, P. Patteri22, M. Pelizaeus4, J. Pellegrino60,62, H. P. Peng (彭海平)44,57, Z. Y. Peng (彭志远)12, K. Peters10,74, J. Pettersson63, J. L. Ping (平加伦)33, R. G. Ping (平荣刚)1,51, A. Pitka4, R. Poling54, V. Prasad44,57, H. R. Qi (漆红荣)2, M. Qi (祁鸣)34, T. Y. Qi (齐天钰)2, S. Qian (钱森)1,44, C. F. Qiao (乔从丰)51, N. Qin (覃拈)64, X. S. Qin4, Z. H. Qin (秦中华)1,44, J. F. Qiu (邱进发)1, K. H. Rashid59,76, C. F. Redmer27, M. Richter4, M. Ripka27, M. Rolo62, G. Rong (荣刚)1,51, Ch. Rosner14, X. D. Ruan (阮向东)12, A. Sarantsev28,72, M. Savrie25, C. Schnier4, K. Schoenning63, W. Shan (单葳)18, X. Y. Shan (单心钰)44,57, M. Shao (邵明)44,57, C. P. Shen (沈成平)2, P. X. Shen (沈培迅)35, X. Y. Shen (沈肖雁)1,51, H. Y. Sheng (盛华义)1, X. Shi (史欣)1,44, J. J. Song (宋娇娇)38, W. M. Song38, X. Y. Song (宋欣颖)1, S. Sosio60,62, C. Sowa4, S. Spataro60,62, G. X. Sun (孙功星)1, J. F. Sun (孙俊峰)15, L. Sun (孙亮)64, S. S. Sun (孙胜森)1,51, X. H. Sun (孙新华)1, Y. J. Sun (孙勇杰)44,57, Y. K Sun (孙艳坤)44,57, Y. Z. Sun (孙永昭)1, Z. J. Sun (孙志嘉)1,44, Z. T. Sun (孙振田)21, Y. T Tan (谭雅星)44,57, C. J. Tang (唐昌建)41, G. Y. Tang (唐光毅)1, X. Tang (唐晓)1, I. Tapan49, M. Tiemens30, D. Toth54, B. Tsednee26, I. Uman50, G. S. Varner52, B. Wang (王斌)1, B. L. Wang (王滨龙)51, C. W. Wang (王成伟)34, D. Wang (王东)36, D. Y. Wang (王大勇)36, Dan Wang (王丹)51, K. Wang (王科)1,44, L. L. Wang (王亮亮)1, L. S. Wang (王灵淑)1, M. Wang (王萌)38, Meng Wang (王蒙)1,51, P. Wang (王平)1, P. L. Wang (王佩良)1, W. P. Wang (王维平)44,57, X. F. Wang (王雄飞)1, Y. Wang (王越)44,57, Y. F. Wang (王贻芳)27, Y. Q. Wang (王亚乾)27, Z. Wang (王铮)1,44, Z. G. Wang (王志刚)1,44, Z. Y. Wang (王至勇)1, Zongyuan Wang (王宗源)1,51, T. Weber4, D. H. Wei (魏代会)11, P. Weidenkaff27, S. P. Wen (文硕频)1, U. Wiedner4, M. Wolke63, L. H. Wu (伍灵慧)1, L. J. Wu (吴连近)1,51, Z. Wu (吴智)1,44, L. Xia (夏磊)44,57, X. Xia38, Y. Xia (夏宇)19, D. Xiao (肖栋)1, Y. J. Xiao (肖言佳)1,51, Z. J. Xiao (肖振军)33, Y. G. Xie (谢宇广)1,44, Y. H. Xie (谢跃红)6, X. A. Xiong (熊习安)1,51, Q. L. Xiu (修青磊)1,44, G. F. Xu (许国发)1, J. J. Xu (徐静静)1,51, L. Xu (徐雷)1, Q. J. Xu (徐庆君)13, Q. N. Xu (徐庆年)51, X. P. Xu (徐新平)42, F. Yan (严芳)58, L. Yan (严亮)60,62, W. B. Yan (鄢文标)44,57, W. C. Yan (闰文成)2, Y. H. Yan (颜永红)19, H. J. Yang (杨海军)39,75, H. X. Yang (杨洪勋)1, L. Yang (杨柳)64, S. L. Yang (杨双莉)1,51, Y. H. Yang (杨友华)

Study ofηð1475ÞandXð1835Þin radiativeJ/ψdecays toγφ

The decay J/psi -> gamma gamma phi is studied using a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector. Two structures around 1475 MeV/c(2) and 1835 MeV/c(2) are observed in the gamma phi invariant mass spectrum for the first time. With a fit on the gamma phi invariant mass, which takes into account the interference between the two structures, and a simple analysis of the angular distribution, the structure around 1475 MeV/c(2) is found to favor an assignment as the eta(1475) and the mass and width for the structure around 1835 MeV/c(2) are consistent with the X(1835). The statistical significances of the two structures are 13.5 sigma and 6.3 sigma, respectively. The results indicate that both eta(1475) and X(1835) contain a sizeable s (s) over bar component

Search for invisible decays of ω and ϕ with J/ψ data at BESIII

Using a data sample of (1310.6±7.0)×106  J/ψ events collected with the BESIII detector operating at the BEPCII collider, we perform the first experimental search for invisible decays of a light vector meson (V=ω, ϕ) via J/ψ→Vη decays. The decay of η→π+π−π0 is utilized to tag the V meson decaying into the invisible final state. No evidence for a significant invisible signal is observed, and the upper limits on the ratio of branching fractions at the 90% confidence level are determined to be B(ω→invisible)B(ω→π+π−π0)<8.1×10−5 and B(ϕ→invisible)B(ϕ→K+K−)<3.4×10−4. By using the world average values of B(ω→π+π−π0) and B(ϕ→K+K−), the upper limits on the decay branching fractions at the 90% confidence level are set as B(ω→invisible)<7.3×10−5 and B(ϕ→invisible)<1.7×10−4, respectively

Measurement of the matrix elements for the decays eta' -&gt; eta pi(+) pi(-) and eta' -&gt; eta pi(0)pi(0)

Based on a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector, the matrix elements for the decays eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0) are determined using 351,016 eta' -> (eta -> gamma gamma)pi' pi(-) and 56,249 eta' -> (eta -> gamma gamma)pi(0) pi(0) events with background levels less than 1%. Two commonly used representations are used to describe the Dalitz plot density. We find that an assumption of a linear amplitude does not describe the data well. A small deviation of the obtained matrix elements between eta' -> eta pi(+) pi(-) and eta' -> eta pi(0)pi(0) is probably caused by the mass difference between charged and neutral pions or radiative corrections. No cusp structure in eta' -> eta pi(0)pi(0) is observed

Study of the decays D+-> eta(('))e(+)nu(e)

The charm semileptonic decays D+ -> eta e(+)nu(e) and D+ -> eta'e(+)nu(e) are studied with a sample of e(+)e(-) collision data corresponding to an integrated luminosity of 2.93 fb(-1) collected at root s = 3.773 GeV with the BESIII detector. We measure the branching fractions for D+ -> eta e(+)upsilon(e) to be (10.74 +/- 0.81 +/- 0.51)x10(-4), and for D+ -> eta'e(+)nu(e) to be (1.91 +/- 0.51 +/- 0.13) x 10(-4), where the uncertainties are statistical and systematic, respectively. In addition, we perform a measurement of the form factor in the decay D+ -> eta e(+)nu(e) . All the results are consistent with those obtained by the CLEO-c experiment

Observation of the Semileptonic Decay D-0 -> a(0)(980)(-)e(+)nu(e) and Evidence for D+ -> a(0)(980)(0)e(+)nu(e)

Using an e(+)e(-) collision data sample of 2.93 fb(-1) collected at a center-of-mass energy of 3.773 GeV by the BESIII detector at BEPCII, we report the observation of D-0 -> a(0)(980)(-)e(+)nu(e) and evidence for D+ -> a(0)(980)(0)e(+)nu(e) with significances of 6.4 sigma and 2.9 sigma, respectively. The absolute branching fractions are determined to be B(D-0 -> a(0)(980)(-)e(+)nu(e)) x B(a(0)(980)(-) -> eta pi(-)) = [1.33(-0.29)(+0.33)(stat) +/- 0.09(syst)] x 10(-4) and B(D+ -> a(0)(980)(0)e(+)nu(e)) x B(a(0)(980)(0) -> eta pi(0)) = [1.66(-0.66)(+0.81)(stat) +/- 0.11(syst) x 10(-4). This is the first time the a(0)(980) meson has been measured in a D-0 semileptonic decay, which would open one more interesting page in the investigation of the nature of the puzzling a(0)(980) states